Lactose production

Uses of lactose production by appHcation include baby and infant formulations (30%), human food (30%), pharmaceuticals (25%), and fermentation and animal feed (15%) (39). It is used as a diluent in tablets and capsules to correct the balance between carbohydrate and proteins in cow-milk-based breast milk replacers, and to increase osmotic property or viscosity without adding excessive sweetness. It has also been used as a carrier for flavorings. 

Processes for crystallization of lactose are well established, with production generally limited to a few large plants. Although a variety of cheese wheys and whey ultrafiltrates can be used for lactose production, sweet whey or ultrafiltrates are preferred (Woychik 1982). The crystallization process has three basic steps ... 

Vromans, H. Lerk, C.F. de Biggelaar, H. Van. Bosch, H. Studies on tableting properties of lactose. VII. The effect of variations in primary particle size and percentage of amorphous lactose in spray-dried lactose products. Int. J. Pharm. 1987, 35, 29-37. 

Hutton JT, Ellen G, Palmer GM, Valley C. Lactose product and method. Linked States Patent No. 3,639,170 1972. 

For lactose production the whey is evaporated to 55-65% solid content, and the concentrate is then seeded and cooled slowly to induce sugar crystallization. The raw lactose (food quality) is recrystallized to yield a raffinade (pharmaceutical-grade lactose). Lactose is used in manufacturing of drugs (tablet filler), dietetic food products, baked products, dehydrated foods, cocoa products, beverages and ice creams. 

Sometimes it is necessary to reslurry the cake discharged from the decanter. This is generally for washing out contaminants from the cake, as in lactose production. It is sometimes done in effluent thickening, and when a greater dryness than is required is produced by the decanter for easy control. Then the cake is back mixed with a feed by-pass which reduces overall flocculant consumption, because the by-pass does not need flocculant. The by-passing material is, of course, 100% recovery. 

Decanters in casein production will often have a centripetal pump discharge to combat foam, and axial flow, as well as clean-in-place systems. Lactose production uses a double-lead conveyor, with on-the-beach rinsing, and a reslurry rinse solids collector, as well, again, as CIP. 

Angberg [148] reviewed the manufacture of lactose products. Recrystallisation from a supersaturated lactose solution below 93.5°C yields almost exclusively a-lactose monohydrate. Crystalline lactose powders with a high content of anhydrous forms are manufactured for direct compression. 

Saccharic acid. Use the filtrate A) from the above oxidation of lactose or, alternatively, employ the product obtained by evaporating 10 g. of glucose with 100 ml. of nitric acid, sp. gr. 1 15, until a syrupy residue remains and then dissolving in 30 ml. of water. Exactly neutralise at the boiling point with a concentrated solution of potassium carbonate, acidify with acetic acid, and concentrate again to a thick syrup. Upon the addition of 50 per cent, acetic acid, acid potassium saccharate sepa rates out. Filter at the pump and recrystaUise from a small quantity of hot water to remove the attendant oxahc acid. It is necessary to isolate the saccharic acid as the acid potassium salt since the acid is very soluble in water. The purity may be confirmed by conversion into the silver salt (Section 111,103) and determination of the silver content by ignition. 

The approximate times of osazone formation in minutes are given in Table 111,139. The product from mannose is the simple hydrazone and is practically white. Arabinose osazone separates first as an oil, whilst that from galactose is highly crystalline. Lactose and maltose give no precipitate from hot solution. 

K. marxianus var. fragilis which utilizes lactose, produces a food-giade yeast product from cheese whey or cheese whey permeates collected from ultrafiltration processes at cheese plants. Again, the process is similar to that used with C. utilis (2,63). The Provesteen process can produce fragiUs yeast from cheese whey or cheese whey permeate at cell concentrations ia the range of 110—120 g/L, dry wt basis (70,73). 

Following ultrafiltration of whey, the permeate passes over a reverse osmosis (qv) membrane to separate the lactose from other components of the permeate. Reverse osmosis can be used to remove water and concentrate soHds in a dairy plant, giving a product with 18% soHds and thus decreasing the difficulty of waste disposal. Concentration of rinse water gives a product with 4—5% total soHds. Proper maintenance of the membrane allows for use up to two years. Membranes are available for use up to 100°C with pH ranges from 1 to 14 the usual temperature range is 0—50°C. 

The ratio of a-lactose [10039-26-6] and P-lactose in dry milk and whey varies according to the speed and temperature of drying. An aqueous solution at equiHbrium at 25°C contains 35% a- and 63% -lactose. The latter is more soluble and sweeter than DL-lactose and is obtained by heating an 80% DL-lactose [63-42-3] solution above 93.5°C, foUowed by drying on a dmm or roUer dryer. Lactose is used for foods and pharmaceutical products. 

Nutritional Value of Milk Products. Milk is considered one of the principal sources of nutrition for humans. Some people are intolerant to one or more components of milk so must avoid the product or consume a treated product. One example is intolerance to lactose in milk. Fluid milk is available in which the lactose has been treated to make it more digestible. The consumption of milk fat, either in fluid milk or in products derived from milk, has decreased markedly in the 1990s. Whole milk sales decreased 12% between 1985 and 1988, whereas the sales of low fat milk increased 165%, and skimmed milk sales increased 48% (35). Nutritionists have recommended that fat consumed provide no more than 30 calories, and that consumption of calories be reduced. Generally, a daily diet of 2000—3000 cal/d is needed depending on many variables, such as gender, type of work, age, body responses, exercise, etc. Further, there is concern about cholesterol [57-88-5] and density of fat consumed. Complete information on the nutritive value of milk and milk products is provided on product labels (36) (see also Table 4). 

Lactose, and the lactose ia substances such as milk and whey, has been hydroly2ed commercially by enzymes to yield products that can be tolerated physiologically much more easily by people who have a lactose iatolerance (40—42). 

A typical fermentation medium for penicillin production contains lactose, com steep Hquot, and calcium carbonate (3,153,154). In most industrial processes the carbohydrate source, glucose, beet molasses, or lactose, is continuously added to the fermentation. The rate of glucose addition must be carefully monitored, by pH or rate of oxygen depletion, because the synthesis of penicillin is markedly reduced in the presence of excess glucose. 

Lactose occurs in milk, mainly free, but to a small extent as a component of higher oligosaccharides. Cow and goat milks contain about 4.5% lactose human milk contains about 7.0%. Lactose is used as an excipient in tablets to provide bulk and rapid disintegration. It is also used in some food products where it contributes body with only about 40% the sweetness of sucrose and enhances colors and flavors. 

Proposed IDE standards for caseiaate are hsted ia Table 4. la most cases the sodium salt is preferred for emulsificatioa the calcium salt is preferred for imitation cheese. Caseia and caseiaates must be stored carefliUy and evaluated for flavor before use ia products. Improperly manufactured or stored caseia—caseiaate has a very stroag, musty off-flavor. Excessive fat coateat, high lactose and moisture contents, and high storage temperatures contribute to undesirable flavor development. 

Whey is the fluid obtained by separatiag the coagulum from cream and/or skim milk, and is a by-product of either caseia or cheese manufacture. The composition of whey is determined by the method of curd formation, curd handling practices, and methods of handling whey as it is separated from the curd. Dried acid whey contains ca 12.5 wt % proteia (total nitrogea x6.38), 11.0 wt % ash, and 59 wt % lactose, whereas sweet whey contains 13.5 wt % proteia, 1.2 wt % fat, 8.4 wt % ash and 74 wt % lactose. The composition varies with the type of acid used (7). 

Whey has been used ia some substitute dairy products but aot as a source of proteia. Whey proteias have beea used ia dairy substitutes only siace the commercialisation of ultrafiltration (qv) technology. Membranes are used that retain proteia and permit water, lactose, and some minerals to pass through as permeate. Proteia coaceatrates are available from both acid and sweet whey and ia coaceatratioas of 35—80 wt % proteia. Whey proteia isolates are commercially available having proteia >90 wt%. The cost of these isolates is too high, however, to make them economical for substitute dairy foods. 

Whey concentration, both of whole whey and ultrafiltration permeate, is practiced successfully, but the solubility of lactose hmits the practical concentration of whey to about 20 percent total sohds, about a 4x concentration fac tor. (Membranes do not tolerate sohds forming on their surface.) Nanofiltration is used to soften water and clean up streams where complete removal of monovalent ions is either unnecessary or undesirable. Because of the ionic character of most NF membranes, they reject polyvalent ions much more readily than monovalent ions. NF is used to treat salt whey, the whey expressed after NaCl is added to curd. Nanofiltration permits the NaCl to permeate while retaining the other whey components, which may then be blended with ordinaiy whey. NF is also used to deacidify whey produced by the addition of HCl to milk in the production of casein. 

Diafiltration If a batch process is run so that the permeate is replaced by an equal volume of fresh solvent, unretained solutes are flushed through the system more efficiently. A major use of UF is fractionation, where a solvent, a retained solute and an unretained solute are present. An example is whey, containing water, protein, and lactose. If the retention of protein is I and the retention of lactose is 0, the concentration of protein in the retentate rises during UF. The ratio of protein to lac tose rises, but the feed concentration of lactose is unchanged in retentate and permeate. Diafiltration dilutes the feed, and permits the concentration of lactose to be reduced. Diafiltration is used to produce high-purity products, and is used to fractionate high-value products. R is always 0 for eveiy component. 

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